U.S. patent application number 14/480132 was filed with the patent office on 2015-01-08 for flexible organic light emitting display and method in an in-cell structure having a touch electrode array for manufacturing the same.
This patent application is currently assigned to LG DISPLAY CO., LTD.. The applicant listed for this patent is LG DISPLAY CO., LTD.. Invention is credited to Ho-Won Choi, Jin-Yeol Kim.
Application Number | 20150011030 14/480132 |
Document ID | / |
Family ID | 47603117 |
Filed Date | 2015-01-08 |
United States Patent
Application |
20150011030 |
Kind Code |
A1 |
Choi; Ho-Won ; et
al. |
January 8, 2015 |
FLEXIBLE ORGANIC LIGHT EMITTING DISPLAY AND METHOD IN AN IN-CELL
STRUCTURE HAVING A TOUCH ELECTRODE ARRAY FOR MANUFACTURING THE
SAME
Abstract
Disclosed are an organic light emitting display that enables
realization of a thin film shape and flexibility, and exhibits
superior contact properties in touch pads based on an improved
structure, and a method for manufacturing the same, wherein a
distance between the outermost surface of the touch pad portion and
the outermost surface of the dummy pad portion in the touch pad
portion is smaller than the distance in a neighboring portion
adjacent to the touch pad portion.
Inventors: |
Choi; Ho-Won; (Daegu,
KR) ; Kim; Jin-Yeol; (Sangju-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG DISPLAY CO., LTD. |
Seoul |
|
KR |
|
|
Assignee: |
LG DISPLAY CO., LTD.
Seoul
KR
|
Family ID: |
47603117 |
Appl. No.: |
14/480132 |
Filed: |
September 8, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13725434 |
Dec 21, 2012 |
8872168 |
|
|
14480132 |
|
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|
Current U.S.
Class: |
438/25 ;
438/34 |
Current CPC
Class: |
G06F 3/0412 20130101;
H01L 51/5237 20130101; H01L 51/56 20130101; H01L 27/3244 20130101;
G06F 3/0447 20190501; H01L 51/50 20130101; H01L 51/524 20130101;
H01L 51/5246 20130101; G06F 3/0446 20190501; H01L 51/5243 20130101;
H01L 27/323 20130101; H01L 33/08 20130101; Y02E 10/549 20130101;
G06F 3/0445 20190501; H01L 51/5203 20130101 |
Class at
Publication: |
438/25 ;
438/34 |
International
Class: |
H01L 51/52 20060101
H01L051/52; H01L 51/56 20060101 H01L051/56 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 13, 2012 |
KR |
10-2012-0088540 |
Claims
1. A method for manufacturing an organic light emitting display
comprising: forming a first etching stopper film and a first buffer
layer on a first substrate, forming a thin film transistor array
including a thin film transistor in each of a plurality of pixels
defined in a matrix form, an organic light emitting diode connected
to each thin film transistor at each pixel, and a protective layer
formed on the first buffer layer such that the protective layer
covers the thin film transistor array and the organic light
emitting diode, in the active region of the first buffer layer, and
forming a dummy pad portion on the dead region of the first buffer
layer; forming a second etching stopper film and a second buffer
layer on a second substrate, forming a touch electrode array in the
active region of the second buffer layer, forming a touch pad
portion in a region corresponding to the dummy pad portion; and
applying a sealant including conductive balls to the touch pad
portion or the dummy pad portion; joining the touch electrode array
to the protective layer, wherein a distance between the outermost
surface of the touch pad portion and the outermost surface of the
dummy pad portion in the touch pad portion is smaller than the
distance in a neighboring portion adjacent to the touch pad
portion.
2. The method according to claim 1, wherein, after the joining, the
conductive balls are compressed to a predetermined thickness
between the touch pad portion and the dummy pad portion.
3. The method according to claim 2, wherein after the joining, the
dead region of the neighboring portion is spaced from the sealant
by a predetermined distance.
4. The method according to claim 1, further comprising: removing
the first substrate and the second substrate; and attaching a film
substrate to an exposed surface of the first etching stopper
film.
5. The method according to claim 4, wherein the removing the first
substrate and the second substrate is carried out by etching or
laser-irradiating the first substrate and the second substrate.
6. A method for manufacturing an organic light emitting display
comprising: forming an organic light emitting array on a first
substrate; forming a protective layer on the organic light emitting
diode; forming a touch electrode array on a second substrate;
bonding the protective layer to the touch electrode array; and
removing the first and second substrates to reduce an overall
thickness of the organic light emitting display and to increase
flexibility thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This present patent document is a divisional of U.S. patent
application Ser. No. 13/725,434, filed Dec. 21, 2012, which claims
priority to Korean Patent Application No. 10-2012-0088540, filed on
Aug. 13, 2012, which is hereby incorporated by reference as if
fully set forth herein.
FIELD
[0002] The present invention relates to an organic light emitting
display, and more particularly, to an organic light emitting
display that enables realization of a thin film shape and
flexibility, and exhibits superior contact properties in touch pads
based on an improved structure, and a method for manufacturing the
same.
BACKGROUND
[0003] Examples of flat panel displays include liquid crystal
displays (LCDs), organic light emitting displays (OLEDs), plasma
display panels (PDPs), quantum dot panels (PDPs), field emission
displays (FEDs), electrophoretic displays (EPDs) and the like.
These displays include a flat display panel realizing an image in
common as an essential component. Such a flat display panel has a
configuration in which a pair of transparent insulating substrates
are joined together such that they face each other via a layer
containing an inherently luminescent or polarizing material or
other optical material interposed therebetween.
[0004] In accordance with the recent trend toward large-size
displays, demand for flat panel displays taking a smaller space
gradually increases. Of these flat panel displays, organic light
emitting display technologies are being rapidly developed.
[0005] Organic light emitting displays do not require any separate
light source and include an organic light emitting diode that
spontaneously emits light in each pixel, to realize display. The
organic light emitting displays attract much attention as
next-generation displays since they advantageously do not require
light sources as well as structures for assembling the light
sources with a display panel, thus having advantages of decrease in
thickness and weight.
[0006] When electric charges are injected into an organic film
formed between an electron injection electrode (cathode) and a hole
injection electrode (anode), electrons pair with holes and the
pairs then decay. At this time, an organic light emitting diode
emits light.
[0007] Meanwhile, there is an increasing demand for incorporating a
touchscreen into an organic light emitting display, where a site
touched by the hand or separate input element is sensed and
information is transferred in response thereto. Such a touchscreen
is being applied by adhesion to the outer surface of the
display.
[0008] Depending on touch sense methods, a touchscreen may be of
resistive, capacitive and infrared sensing types. In consideration
of ease of manufacture, sensing force and the like, capacitive type
touchscreens attract much attention in small models.
[0009] Hereinafter, a touchscreen-integrated organic light emitting
display of related art will be described with reference to the
annexed drawings.
[0010] FIG. 1 is a sectional view illustrating a touchscreen
organic light emitting display of related art.
[0011] As shown in FIG. 1, the touchscreen-integrated organic light
emitting display includes an organic light emitting display panel
1, a touchscreen 2 and a cover window 3 laminated in this order
from the bottom and includes first and second adhesive layers 15
and 25 disposed between the respect layers.
[0012] Here, the organic light emitting display panel 1 includes a
substrate, a thin film transistor array having a matrix form
disposed on the substrate, and an organic light emitting diode
connected to each thin film transistor of the thin film transistor
array, and includes a protective film and a polarizing layer that
cover the top of the organic light emitting diode. In this case,
the first adhesive layer 15 corresponds to the polarizing layer of
the organic light emitting display panel 1.
[0013] The touchscreen-integrated organic light emitting display of
related art has the following disadvantages.
[0014] First, when an organic light emitting display panel and a
touchscreen are independently formed, and the touchscreen is then
attached to the organic light emitting display panel, the organic
light emitting display panel and the touchscreen require separate
glasses, thus resulting in increased hardness and thickness, and
making realization of thin and flexible organic light emitting
displays impossible.
[0015] Second, the organic light emitting display panel and the
touchscreen have different panel shapes, thus making processes for
forming these components complicated and thus decreasing yield and
price competiveness.
[0016] Third, if the touchscreen is configured as an in-cell type,
a pad portion of the touchscreen faces an inside, that is, a side
of a pad portion of an organic light emitting display panel. In
this case, a bonding process is performed using a sealant including
conductive balls. Herein, relatively small conductive balls may
have contact defects due to difference in diameter between the
normal conductive balls. Also, a compression level of conductive
balls is changed depending on a pressure applied during bonding and
contact defects may thus occur during the bonding process.
SUMMARY
[0017] Accordingly, the present disclosure is directed to an
organic light emitting display and a method for manufacturing the
same that substantially obviate one or more problems due to
limitations and disadvantages of the related art.
[0018] An object of the present disclosure is to provide an organic
light emitting display that enables realization of a thin film
shape and flexibility, and exhibits superior contact properties in
touch pads based on an improved structure, and a method for
manufacturing the same.
[0019] Additional advantages, objects, and features of the present
disclosure will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the present disclosure may be realized and attained
by the structure particularly pointed out in the written
description and claims hereof as well as the appended drawings.
[0020] To achieve these objects and other advantages and in
accordance with the purpose of the present disclosure, as embodied
and broadly described herein, provided is an organic light emitting
display including: a first buffer layer and a second buffer layer
having an active region and a dead region and facing each other; a
thin film transistor array including a thin film transistor in each
of a plurality of pixels defined in a matrix form on the active
region of the first buffer layer; an organic light emitting diode
connected to each thin film transistor at each pixel; a protective
layer formed on the first buffer layer such that the protective
layer covers the thin film transistor array and the organic light
emitting diode; a touch electrode array formed on the active region
of the second buffer layer; an adhesive layer contacting the
protective layer and the touch electrode array, respectively; a
touch pad portion formed on a part of the dead region of the second
buffer layer; a dummy pad portion facing the touch pad portion on
the dead region of the first buffer layer; and a sealant including
a plurality of conductive balls between the touch pad portion and
the dummy pad portion, wherein a distance between the outermost
surface of the touch pad portion and the outermost surface of the
dummy pad portion in the touch pad portion is smaller than the
distance in a neighboring portion adjacent to the touch pad
portion.
[0021] Also, the touch pad portion may include a plurality of touch
pad electrodes spaced from one another, the dummy pad portion may
comprise a plurality of dummy electrodes corresponding to the touch
pad electrodes.
[0022] The conductive balls may be compressed to a predetermined
thickness between the touch pad portion and the dummy pad
portion.
[0023] The dead region of the neighboring portion may be spaced
from the sealant by a predetermined distance.
[0024] Meanwhile, the touch pad electrode may have a laminate
structure including: a metal pattern; a transparent electrode
pattern overlapping the metal pattern; and at least one interlayer
insulating film disposed between the metal pattern and the
transparent electrode pattern.
[0025] Here, at least one interlayer insulating film may be an
organic film.
[0026] Also, the touch electrode array may include: a metal bridge
formed in the same layer as the metal pattern on the second buffer
layer; a plurality of first transparent channel electrodes
electrically connected to the metal bridge while overlapping the
metal bridge in the same layer as the transparent electrode
pattern, the first transparent channel electrodes being spaced in a
first direction; and a second transparent channel electrode formed
in a second direction while traversing the metal bridge in the same
layer as the first transparent channel electrode.
[0027] Also, the touch pad electrode may further include a common
transparent electrode pattern that is connected to the transparent
electrode pattern and overlaps the same.
[0028] In this case, the organic light emitting display may further
include a common transparent electrode in the same layer as the
common transparent electrode pattern such that the common
transparent electrode covers the first transparent channel
electrode and the second transparent channel electrode.
[0029] Also, the organic light emitting display may further include
a first interlayer insulating film between the metal bridge and a
layer of the first transparent channel electrode and the second
transparent channel electrode; and a second interlayer insulating
film formed between the common transparent electrode and the layer
of the first transparent channel electrode and the second
transparent channel electrode.
[0030] At least one interlayer insulating film may be removed from
the dead region of the neighboring portion.
[0031] Also, the first interlayer insulating film may be removed
from a region excluding the metal bridge intersecting the second
transparent electrode channel and the touch pad electrode.
[0032] Meanwhile, the dummy electrode may include a gate insulating
film, a gate electrode layer, an intermediate insulating film and a
source metal layer laminated on the first buffer layer.
[0033] Also, the organic light emitting display may further include
a first etching stopper and a second etching stopper film formed on
the back surfaces of the first buffer layer and the second buffer
layer, respectively. In this case, the organic light emitting
display may further include a film substrate formed on the back
surface of the first etching stopper film.
[0034] Also, the organic light emitting display may further include
a cover glass formed on a back surface of the second etching
stopper film.
[0035] Meanwhile, the first buffer layer and the second buffer
layer may have a laminate structure including a plurality of
inorganic films.
[0036] Also, the film substrate may be a plastic insulating
film.
[0037] Also, the first etching stopper film and the second etching
stopper film may include polyimide or photoacryl.
[0038] In accordance with another aspect of the present invention,
provided is a method for manufacturing an organic light emitting
display including: forming a first etching stopper film and a first
buffer layer on a first substrate, forming a thin film transistor
array including a thin film transistor in each of a plurality of
pixels defined in a matrix form, an organic light emitting diode
connected to each thin film transistor at each pixel, and a
protective layer formed on the first buffer layer such that the
protective layer covers the thin film transistor array and the
organic light emitting diode, in the active region of the first
buffer layer, and forming a dummy pad portion on the dead region of
the first buffer layer; forming a second etching stopper film and a
second buffer layer on a second substate, forming a touch electrode
array in the active region of the second buffer layer, forming a
touch pad portion in a region corresponding to the dummy pad
portion; and applying a sealant including conductive balls to the
touch pad portion or the dummy pad portion, attaching an adhesive
layer to the touch electrode array or the protective layer and
performing a joining process, wherein a distance between the
outermost surface of the touch pad portion and the outermost
surface of the dummy pad portion in the touch pad portion is
smaller than the distance in a neighboring portion adjacent to the
touch pad portion.
[0039] After the joining process, the conductive balls may be
compressed to a predetermined thickness between the touch pad
portion and the dummy pad portion.
[0040] After the joining process, the dead region of the touch pad
portion neighboring portion may be spaced from the sealant by a
predetermined distance.
[0041] The method may further include: removing the first substrate
and the second substrate; and attaching a film substrate to an
exposed surface of the first etching stopper film.
[0042] The removing the first substrate and the second substrate
may be carried out by etching or laser-irradiating the first
substrate and the second substrate.
[0043] It is to be understood that both the foregoing general
description and the following detailed description of the present
disclosure are exemplary and explanatory and are intended to
provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The accompanying drawings, which are included to provide a
further understanding of the present disclosure and are
incorporated in and constitute a part of this application,
illustrate embodiment(s) of the invention and simultaneously with
the description serve to explain the principle of the invention. In
the drawings:
[0045] FIG. 1 is a sectional view illustrating a
touchscreen-integrated organic light emitting display of related
art.
[0046] FIG. 2 is a plan view illustrating an organic light emitting
display according to the present disclosure.
[0047] FIG. 3 is a cross-sectional view taken along the line I-I'
of FIG. 2.
[0048] FIG. 4 is a graph showing distribution of conductive balls
according to diameter.
[0049] FIG. 5 is a graph showing a ratio of conductive balls
contacting a substrate.
[0050] FIG. 6 is a graph showing a ratio of conductive balls
contacting a substrate before and after compression when conductive
balls have different diameters.
[0051] FIG. 7 is a cross-sectional view illustrating a bonding
process in the pad and a pad neighboring portion of FIG. 2.
[0052] FIG. 8 is a cross-sectional view illustrating a pad, a pad
neighboring portion and an active region of an organic light
emitting display according to a first embodiment of the present
disclosure.
[0053] FIG. 9 is a cross-sectional view illustrating a pad, a pad
neighboring portion and an active region of an organic light
emitting display according to a second embodiment of the present
disclosure.
[0054] FIG. 10 is a plan view illustrating a region "A" of FIG. 2
according to a modified embodiment of the second embodiment.
[0055] FIGS. 11A and 11B are an enlarged plan view and a sectional
view illustrating a region "B" of FIG. 10, respectively.
[0056] FIG. 12 is a plan view illustrating a region "A" according
to the second embodiment of the present disclosure.
[0057] FIGS. 13A and 13B are an enlarged plan view and a sectional
view of a region "C" of FIG. 12, respectively.
DETAILED DESCRIPTION
[0058] Reference will now be made in detail to the preferred
embodiments of the present disclosure, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0059] Hereinafter, an organic light emitting display and a method
for manufacturing the same will be described in detail with
reference to the annexed drawings.
[0060] An organic light emitting display according to the present
disclosure has a touch sensing function and has a reduced thickness
and increased flexibility. According to the present disclosure, a
thin film transistor and an organic light emitting array are formed
on a first substrate, whereas a touch electrode array is formed on
a second substrate. The first and second substrates are joined
together, followed by removing the hard and thick first and second
substrates by laser irradiation or etching to reduce thickness and
to increase flexibility. In the organic light emitting display
according to the present disclosure, a pad portion of the touch
electrode array faces a pad portion of the organic light emitting
array, and these pad portions are connected to each other via a
conductive ball to allow for transfer of signals to the touch
electrode array and detection of signals from the touch electrode
array.
[0061] Hereinafter, an in-cell organic light emitting display in
which a touch electrode array is provided inside a cover glass will
be described.
[0062] FIG. 2 is a plan view illustrating an organic light emitting
display according to the present disclosure. FIG. 3 is a
cross-sectional view taken along the line I-I' of FIG. 2.
[0063] As shown in FIGS. 2 and 3, the organic light emitting
display according to the present disclosure includes an organic
light emitting array 150 and a touch electrode array 230 that are
joined to each other via an adhesive layer 400. The organic light
emitting array 150 and the touch electrode array 230 have different
sizes, and are formed at an inside of a film substrate 1000 and at
an inside of a cover glass 3000, respectively.
[0064] The organic light emitting array 150 and the touch electrode
array 230 are not directly formed on the film substrate 1000 or the
cover glass 3000. Instead, these arrays are formed by separately
preparing first and second substrates (both not shown) made of
glass, followed by joining the substrates via an adhesive layer
disposed between the organic light emitting array 150 and the touch
electrode array 230. The joining of the substrates is performed
while keeping the first and second substrates. Thereafter, the
first and second substrates are removed by laser irradiation or
etching to achieve thin film and flexibility. In this case, as
shown in FIG. 2, the first and second substrates formed of glass
materials are removed and the film substrate 1000 and the cover
glass 3000 are adhered to the bottom of the exposed arrays,
respectively, in order to protect these arrays.
[0065] Here, a film adhesive layer 1100, a first etching stopper
layer 120, a first buffer layer 130 and a thin film transistor
array 140 and an organic light emitting array 150 are formed on the
film substrate 1000 in this order. A protective layer 160 is formed
to cover the organic light emitting array 150. A second etching
stopper layer 210, a second buffer layer 220 and a touch electrode
array 230 are disposed on the cover glass 3000. Here, the touch
electrode array 230 is disposed to face the organic light emitting
array 150. As shown in the illustrative embodiment, the protective
layer 160 directly contacts a bottom surface of the adhesive layer
400 and the touch electrode array 230 directly contacts a top
surface of the adhesive layer 400.
[0066] An active region and a dead region are defined in each of
the first buffer layer 130 and the second buffer layer 220. The
touch electrode array 230, the organic light emitting array 150 and
thin film transistors present in the thin film transistor array 140
excluding a pad portion are formed in the active region. The touch
electrode pad portion 2350 and the pad portion of the thin film
transistor array are defined in part of the dead region.
[0067] The first etching stopper layer 120 and the second etching
stopper layer 210 function to prevent damage to an internal array,
in addition to the first and second substrates made of glass
materials during laser irradiation or etching.
[0068] Also, the first buffer layer 130 and the second buffer layer
220 may be formed by sequentially laminating the same type of
inorganic film such as an oxide film (SiO.sub.2) or nitride film
(SiNx), or alternatively laminating different types of inorganic
films. The first and second buffer layers 130 and 220 serve as
barriers to prevent permeation of moisture or exterior air into the
organic light emitting array 150 after the second substrate is
joined to the first substrate.
[0069] Also, both the touch pad portion 2350 and the touch
electrode array 230 are formed on the same surface of the second
buffer layer 220.
[0070] The touch pad portion 2350 is connected to the pad portion
of the thin film transistor array 140 via a sealant 450 including a
conductive ball 455, when the upper and lower substrates are joined
to each other via the adhesive layer 400. The adhesive layer 400
functions to prevent permeation of moisture and directly contacts
the protective layer 160 that covers the organic light emitting
array 150, thus preventing permeation of exterior air into the
organic light emitting array 150 and more certainly prevents
permeation of moisture, in addition to the functions of the
protective layer 160.
[0071] Here, the thin film transistor array 140 including the pad
portion has a side that protrudes from the touch electrode array
230. This configuration aims at providing, at the protrusion, an IC
500 (not shown) that transfers a signal to simultaneously drive the
touch electrode array and the thin film transistor array, and the
organic light emitting array. Although not shown, the IC 500 is
connected through lines (not shown) formed on the IC 500 and the
first buffer layer 130 to driving pads and dummy pads of the thin
film transistor array. Also, the IC 500 is bonded and connected to
a flexible printed circuit board (FPCB, not shown) and may be
controlled by a controller (not shown) provided in the FPCB. The
dummy pad is formed in the same layer as a metal constituting a
gate or data line in a region corresponding to the touch pad
portion among the dead region disposed out of the active
region.
[0072] The touch pad portion 2350 is formed on the second buffer
layer 220 and is formed at both edges of the side adjacent to a
portion where the first buffer layer 130 protrudes more than the
second buffer layer 220. Also, the touch pad portion 2350 formed at
one edge is divided into a plurality of pad electrodes to enable
voltage application or detection of first electrodes arrayed in an
X-axis direction in the touch electrode array, and the touch pad
portion 2350 formed at the other edge is divided into a plurality
of pad electrodes to enable voltage application or detection of
second electrodes arrayed in an Y-axis direction.
[0073] The conductive ball 455 connected to the touch pad portion
2350 is electrically connected to a dummy electrode (not shown)
formed out of the thin film transistor array 140.
[0074] Meanwhile, as shown in FIG. 3, the organic light emitting
display according to the present disclosure includes a film
substrate 1000, a first etching stopper film 120 and a first buffer
layer 130 formed in this order on the film substrate 1000, a thin
film transistor array 140 having a thin film transistor in each
pixel defined in a matrix form on the first buffer layer 130, an
organic light emitting array 150 connected to the thin film
transistor of each pixel, a protective layer 160 that covers the
thin film transistor array 140 excluding the pad portion and the
organic light emitting array 150, a touch electrode array 230
adhered to the protective layer via an adhesive layer 400
interposed between the protective layer 160 and the touch electrode
array 230, and a second buffer layer 220 and a second etching
stopper film 210 formed in this order on the touch electrode array
230, and includes a cover glass 3000 disposed on the second etching
stopper film 210.
[0075] Here, the cover glass 3000 may be adhered to the second
etching stopper film 210 via an adhesive layer therebetween, or may
be disposed on the second etching stopper film 210 by a mechanical
method or another method. The cover glass 3000 protects internal
arrays from damage caused by direct touch of a user.
[0076] The organic light emitting display according to the present
disclosure can have reduced thickness by omitting a glass
substrate, which has a thickness of about 0.7 mm, which is the
thickest among components in the display, and which would otherwise
increase the overall thickness of the organic light emitting
display. Moreover, the organic light emitting can realize a
bendable or flexible display by using a plastic insulating film as
the film substrate 1000 to support the thin film transistor array
140, the organic light emitting array 150 and the touch electrode
array 230.
[0077] In addition, in the process of forming arrays such as the
thin film transistor array 140, the organic light emitting array
150 and the touch electrode array 230 on the film substrate, the
film substrate may be thermally expanded by heat applied to
apparatuses for depositing or patterning the arrays, thus making
normal processing impossible. In order to prevent this phenomenon,
formation of arrays is carried out by forming etching stopper films
120 and 210 and buffer layers 130 and 220 under the thin film
transistor array 140 and the touch electrode array 230,
respectively, on the glass substrate, before formation of the thin
film transistor array 140 and formation of the touch electrode
array 230, and then loading the glass substrate in an apparatus for
deposition or patterning.
[0078] Meanwhile, the thin film transistor array 140 includes a
plurality of gate lines and a plurality of data lines that
intersect each other to define pixels. The thin film transistors
are formed at the respective intersections between the gate lines
and the data lines. A pad portion of the thin film transistor array
140 is obtained by forming a pad portion metal in the process of
forming the gate and data lines.
[0079] Also, the organic light emitting array 150 includes a first
electrode formed at least in the pixel, a second electrode formed
in an upper layer spaced from the first electrode, and an organic
light emitting layer formed between the first and second
electrodes. Here, the first electrode may be connected to a drain
electrode of the thin film transistor.
[0080] In addition, the first etching stopper film 120 and the
second etching stopper film 210 may be for example formed of
polyimide or photo-acryl.
[0081] The first and second etching stopper films 120 and 210 have
a thickness of about 1 .mu.m to about 20 .mu.m.
[0082] Also, the first buffer layer 130 and the second buffer layer
220 function to prevent permeation of oxygen or moisture into
organic films provided in the organic light emitting array and
serve as barriers to prevent permeation of exterior air or moisture
injected from a lower part.
[0083] The first buffer layer 130 and the second buffer layer 220
include a plurality of inorganic films. For example, the inorganic
films may be formed by continuously or alternatively laminating
SiNx or SiO.sub.2. It can be seen from experimentation that, when
two or more layers are laminated to a thickness of about 5,000
.ANG. to 6,500 .ANG. as the first and second buffer layers 130 and
220, permeation of exterior air or moisture can be prevented. A
total thickness of the first and second buffer layers 130 and 220
is 1 .mu.m or less, which does not increase the thickness of the
touchscreen-integrated display device.
[0084] The touch electrode array 230 includes a first transparent
channel electrode (not shown) and a second transparent channel
electrode (not shown) that intersect each other, and a touch pad
(provided in a touch pad portion) to transfer a signal to the first
and second transparent channel electrodes. A thin film transistor
array including the dummy metal is shown in FIG. 3 and a touch
electrode layer is shown in the form of a single layer including
the touch pad, and the first and second transparent channel
electrodes, but these layers are patterned according to respective
electrodes.
[0085] Here, the first and second transparent channel electrodes
are formed of a transparent electrode, the touch pad includes a
metal pad layer that has high conductivity and superior
light-shielding properties (the same layer as the metal bridge),
and a transparent electrode pattern which is the same layer as the
transparent electrode constituting the first and second transparent
channel electrodes. Also, the first and second transparent channel
electrodes may be disposed in the same layer or different layers.
For example, when the first and second transparent channel
electrodes are present in the same layer, a separate metal bridge
that contacts the first transparent channel electrodes or the
second transparent channel electrodes adjacent to other layers is
provided at the intersection between the first and second
transparent channel electrodes, to prevent short-circuit between
the first and second transparent channel electrodes.
[0086] In the in-cell organic light emitting display described
above, contact between the touch pad portion and the dummy pad
portion formed in the thin film transistor array via conductive
balls may be difficult or defective due to difference in diameter
between conductive balls 455 or pressure applied during a bonding
process, thus undesirably increasing resistance.
[0087] FIG. 4 is a graph showing distribution of conductive balls
according to diameter.
[0088] For example, conductive balls (particles) having a mean
diameter of 7 .mu.m, as shown in FIG. 4, may have a diameter
distribution in the range of about 6 .mu.m to 8 .mu.m, due to
manufacturing tolerance during the formation of conductive
balls.
[0089] FIG. 5 is a graph showing a ratio of conductive balls
contacting a substrate. FIG. 6 is a graph showing a ratio of
conductive balls contacting a substrate before and after
compression when there is a difference in diameter between
conductive balls.
[0090] As can be seen from FIG. 6, the conductive balls are elastic
and a contact area between the conductive balls and the substrate
is thus varied depending on applied pressure. As the applied
pressure increases, the contact area between the conductive balls
and the substrate increases.
[0091] As can be seen from FIG. 6, in particular, when a plurality
of conductive balls 55 having different diameters are formed on the
substrate 10, if no pressure is applied to the substrate 10 or a
counter substrate 20 disposed opposite to the substrate 10, only
conductive balls having a large diameter contact the counter
substrate 20. However, when a compressive force of 10% or more is
applied thereto, conductive balls having a small diameter also
contact the counter substrate 20.
[0092] This means that a predetermined pressure or more is required
so that all conductive balls contact an opposite pad portion during
the bonding process due to difference in diameter between the
conductive balls. However, there is a limitation on arbitrary
increase in applied pressure, since the pressure applied during
bonding is predetermined and pattern stability in the active region
should be considered.
[0093] Hereinafter, how to avoid contact defects through structural
change in the organic light emitting display of the present
disclosure will be described.
[0094] FIG. 7 is a cross-sectional view illustrating a bonding
process in the pad and a pad neighboring portion of FIG. 2. FIG. 7
illustrates an organic light emitting display including an in-cell
type touch electrode array according to one embodiment of the
present invention. Considering the pad electrode and the pad
electrode neighboring portion, a step between upper and lower parts
occurs in a region corresponding to a sealant 450.
[0095] FIG. 7 illustrates a bonding process. The first and second
substrates 100 and 300 made of a glass component remain un-removed
on the rear surface of the first etching stopper film 120 and the
second etching stopper film 210, respectively. That is, the bonding
process is performed under the condition that the glass substrate
is not removed. After the touch pad electrode is bonded to the
dummy electrode of the thin film transistor array, the first and
second substrates 100 and 300 are removed.
[0096] Regarding a substantial lamination order, an amorphous
semiconductor layer 110, a first etching stopper film 120, a first
buffer layer 130, a thin film transistor array 140 and an organic
light emitting device array 150 are sequentially formed on the
first substrate 100. In the drawing, excluding an active region,
only the pad electrode portion and the pad electrode neighboring
portion are present and the organic light emitting device array 150
is omitted.
[0097] As shown in FIG. 7, the touch pad electrode 2351a includes a
metal pattern 231a in the same process as the metal bridge of the
touch electrode array 230, and a transparent electrode pattern 233a
and a common transparent electrode pattern 235a formed in the same
process as the first and second transparent channel electrodes.
That is, the touch pad electrode 2351a is formed by laminating a
metal formed during three different processes and at least one
transparent electrode pattern.
[0098] In this case, the pad electrode neighboring portion is not
provided with an electrode and includes the second interlayer
insulating film 234 in the active region. Also, the second
interlayer insulating film 234 is an organic film.
[0099] In this regard, the metal pattern 231a has a thickness of
about 1,000 to about 3,000 .ANG., and the transparent electrode
pattern 233a and the common transparent electrode pattern 235a have
a considerably small thickness of about 300 to about 800 .ANG. and
about 75 to about 250 .ANG., respectively. The thickness of the
common transparent electrode pattern 2351a having a laminate
structure including three layers is smaller than the thickness (2
to 3 .mu.m) of the second interlayer insulating film 234 formed of
an organic film 234. As a result, a distance is present between the
outermost surface of the touch pad electrode 2351a and the
conductive ball 455 present in the sealant 450. This distance
between the conductive ball 455 and the touch pad electrode 2351a
may make electric contact between the pad electrode 2351a and the
dummy electrode 1400 impossible.
[0100] Meanwhile, the dummy electrode 1400 includes a gate
insulating film 141, a gate electrode layer 142, an intermediate
insulating film 143 and a source metal layer 144 which are
laminated on a first buffer layer 130.
[0101] The source metal layer 144 is removed from the neighboring
portion of the dummy electrode 1400 to expose the intermediate
insulating film 143. As a result, a distance "a" is present between
the exposed intermediate insulating film 143 and the sealant
450.
[0102] However, as shown in FIG. 7, since the distance "b" between
the afore-mentioned pad electrode 2351a and the sealant 450 is
larger than the distance "a" due to the thickness of the second
interlayer insulating film 234, the conductive balls 455 may be
spaced from the pad electrode 2351a by applying a predetermined
pressure, making the distance "a" zero. In this case, a contact
defect occurs.
[0103] In the test of the present disclosure, when the second
interlayer insulating film 234 has a thickness of about 2.1 .mu.m,
the metal pattern 231a, the transparent electrode pattern 233a and
the common transparent electrode pattern 235a have thicknesses of
2000 .ANG., 500 .ANG. and 125 .ANG., respectively, the distance "b"
is an about 1.8 .mu.m, and the distance "a" between the thin film
transistor array 140 corresponding to the pad electrode neighboring
portion and the sealant 450 is 3,000 .ANG., as a result of removal
of the source metal layer 144. In this case, a pressure should be
applied so that the conductive ball 445 is compressed to a
thickness of 1.5 .mu.m or more and thus contacts the dummy
electrode 1400 and the touch pad electrode 2351a. Also, in
consideration of difference between the conductive balls 445, a
pressure should be applied so that each conductive ball is
compressed to a thickness of 1.5 .mu.m or more. When the pressure
is insufficient, contact defects may occur in the structure shown
in FIG. 7.
[0104] In this regard, there is a limitation on the amount of
pressure applied during the bonding process. Accordingly, the
organic light emitting display of the present disclosure improves
electric contact between the conductive ball, and the pad electrode
and the dummy electrode, and this configuration will be described
in detail.
[0105] In the following drawings, the layers constituting the touch
electrode array are not drawn to scale and are shown to have
similar thicknesses. Generally, the interlayer insulating film has
the largest thickness of about 1.5 .mu.m to about 4 .mu.m among the
layers constituting the array and the metal layer has a thickness
of about 2,000 .ANG. to about 4,000 .ANG.. The transparent
electrode layer has a thickness of about 300 to about 800 .ANG.,
and the common transparent electrode layer has a thickness of about
75 to 250 .ANG.. That is, the layers have different thickness.
However, as shown in the drawings, the layers formed in common in
the pad electrode, the pad electrode neighboring portion and the
active region cause no step between regions and the respective
layers are shown to have similar thickness.
[0106] FIG. 8 is a cross-sectional view illustrating a pad, a pad
neighboring portion and an active region of an organic light
emitting display according to a first embodiment of the present
invention.
[0107] A state immediately after bonding is shown in the
cross-sectional views of FIGS. 8 and 9. The second substrate 300
and the first substrate 100 disposed in upper and lower parts still
remain unremoved.
[0108] As shown in FIG. 8, the organic light emitting display
according to the first embodiment of the present invention includes
a first buffer layer 130 and a second buffer layer 220 which
include an active region and a dead region and face each other, a
thin film transistor array 140 including a thin film transistor in
each of pixels defined in a matrix form in the active region of the
first buffer layer 130, an organic light emitting array 150
including an organic light emitting diode connected to the thin
film transistor of each pixel, a protective layer 160 formed on the
first buffer layer 130 such that it covers the thin film transistor
array 140 and the organic light emitting array 150, a touch
electrode array 230 formed in the active region of the second
buffer layer 220, an adhesive layer 400, the top and bottom of
which contact the protective layer 160 and the touch electrode
array 230, respectively, a touch pad portion (represented by "2350"
in FIG. 2) formed in a predetermined part of the dead region of the
second buffer layer 220, a dummy pad portion formed in the dead
region of the first buffer layer 130 such that it faces the touch
pad portion, and a sealant 450 including a plurality of conductive
balls 455 positioned between the touch pad portion and the dummy
pad portion.
[0109] Also, the touch pad portion includes a plurality of touch
pads 2351b, and the dummy pad portion includes dummy electrodes
1400 corresponding to the touch pads 2351b.
[0110] Here, a distance between the uppermost surface of the touch
pad electrode 2351b and the uppermost surface of the dummy
electrode 1400 in the pad portion is smaller than the distance in
the neighboring portion. In the drawing, the distance of the pad
electrode is "a+c" smaller than that of the pad electrode
neighboring portion.
[0111] In this case, the first distance "a" represents a distance
between the sealant 450 and the thin film transistor array 140. The
first distance "a" is formed as a result of removal of the source
metal layer 144 from the pad electrode neighboring portion of the
thin film transistor array 140. The second distance "c" represents
a distance between the second interlayer insulating film 234 and
the sealant 450 in the pad electrode neighboring portion.
[0112] In the first embodiment, a first interlayer insulating film
232 corresponding to the touch pad electrode is further provided,
although the second interlayer insulating film 234 included in the
pad electrode neighboring portion adjacent thereto is thicker than
the metal layer or the transparent electrode layers. The first
interlayer insulating film 232 having a similar thickness to the
second interlayer insulating film 232 is also provided in the touch
pad electrode 2351b. The touch pad electrode 2351b is thus formed
to have a step higher than the neighboring portion.
[0113] That is, the touch pad portion includes a plurality of touch
pad electrode 2351bs two-dimensionally spaced from one another.
Each touch pad electrode 2351b further includes the first
interlayer insulating film 232 interposed between the metal pattern
231a and the transparent electrode pattern 233a, in addition to the
metal pattern 231a, the transparent electrode pattern 233a and the
common transparent electrode pattern 235a, along a vertical
direction, in order to increase the height of the step. In FIG. 7,
only one first interlayer insulating film 232 is interposed between
the electrode layer and the transparent electrode pattern, but the
present disclosure is not limited to this structure. That is, two
or more interlayer insulating films can be further provided to
maximize a step between the pad electrode and the pad electrode
neighboring portion. Here, the interlayer insulating film included
in the touch pad electrode 2351a may be formed during formation of
the touch electrode array 230, which is a component that may be
formed without an additional process.
[0114] Here, only a part of the touch pad electrode 2351b is shown.
A contact hole is provided in a part of the first interlayer
insulating film 232 between the metal pattern 231a and the
transparent electrode pattern 233a, thus enabling electric
contact.
[0115] Meanwhile, the dummy electrode 1400 has a configuration in
which a gate insulating film 141, a gate electrode layer 142, an
intermediate insulating film 143 and a source metal layer 144 are
laminated in this order on the first buffer layer 130.
[0116] The conductive ball 455 in the sealant 450 is connected to
the upper and lower touch pads 2351b and the dummy electrode 1400
even upon application of low pressure during the bonding process,
since the touch pad neighboring portion has an "a+c" greater
distance than the touch pad, thus improving contact
characteristics. As a result, after the bonding process, the
conductive ball 455 is pressed to a predetermined thickness between
the touch pad portion and the dummy pad portion. This structure
causes a decrease in contact resistance, improvement in contact
characteristics and thus improvement in touch signal
sensitivity.
[0117] In this case, a second distance "c" is present between the
second interlayer insulating film 234 and the sealant 450 in the
dead region of the touch pad portion neighboring portion, and a
first distance "a" is present between the intermediate insulating
film 143 and the sealant 450 in the dummy electrode neighboring
portion.
[0118] Meanwhile, one or more interlayer insulating films 234 and
232 are preferably organic films. This aims at providing interlayer
insulation between the electrode layer and the transparent
electrode pattern in the touch electrode array 230 and securing a
predetermined thickness between the metal layer and the transparent
electrode pattern which are different layers.
[0119] A flat layer 145 may be further provided on the outermost
surface of the thin film transistor array 140 in the active
region.
[0120] Also, the touch electrode array 230 of the active region
includes the metal bridge 231 formed in the same layer as the metal
pad layer 231a on the second buffer layer, a plurality of first
transparent channel electrodes (represented by "2331" in FIG. 10)
which are electrically connected to the metal bridge 231 while
overlapping the metal bridge 231 and are spaced from one another in
a first direction in the same layer as the transparent electrode
pattern 233a, and a transparent metal layer 233 that includes a
second transparent channel electrode 2332 that traverses the metal
bridge and is formed in a second direction in the same layer as the
first transparent channel electrode.
[0121] In the illustrated drawing, a common transparent electrode
235 overlaps the transparent metal layer 233 and the second
interlayer insulating film 234 constituting the first and second
transparent channel electrodes. If desired, the common transparent
electrode 235 may be omitted. The common transparent electrode 235
is a floating state which functions to shield effects of driving
signals of the thin film transistor array or the organic light
emitting array that faces the same on the touch electrode array
230.
[0122] In this case, the touch pad 2351a of the touch pad portion
may also further include a common transparent electrode pattern
235a that overlaps the transparent electrode pattern 233a and is
connected to the transparent electrode pattern 233a.
[0123] Here, in the dead region of the touch pad portion
neighboring portion, at least one interlayer insulating film (in
the drawing, first interlayer insulating film) may be removed.
[0124] Meanwhile, reference numeral "145" represents a passivation
layer 145 formed on the outermost surface of the thin film
transistor array 140 in the active region.
[0125] Also, the organic light emitting array 150 includes an anode
151, an organic light emitting layer 152 and a cathode 153. This
configuration is a minimal unit. A bank (not shown) may be included
between pixels in order to isolate the organic light emitting layer
152 into pixel units, and an organic layer may be added or changed
in order to improve luminous efficacy between the anode 151 and the
cathode 153.
[0126] Also, first and second etching stopper films 120 and 210 may
be formed on the bottom of the first buffer layer 130 and the
second buffer layer 220, respectively. The first etching stopper
film 120 and the second etching stopper film 210 may be polyimide
or photoacryl.
[0127] In this case, after the bonding process, a film substrate
(represented by "1000" in FIG. 2) may be further formed on the
bottom of the first etching stopper film 120. Here, the film
substrate 1000 may be formed of a plastic insulating film for
realization of thinness and flexibility.
[0128] Also, after removal of the substrate (glass), a cover glass
(represented by "3000" in FIG. 2) may be further formed on the
second etching stopper film 210.
[0129] Meanwhile, the first buffer layer 130 and the second buffer
layer 220 may have a laminate structure including a plurality of
inorganic films.
[0130] Also, the protective layer 160 includes an inorganic film
161, an organic film 162 and an inorganic film 163 which are
laminated in this order. Based on the structure including organic
and inorganic films which are alternately laminated, the protective
layer 160 primarily functions to prevent permeation of moisture
into the organic light emitting array 150.
[0131] Also, reference numerals "205" and "110" represent a nitride
layer and an amorphous semiconductor layer, respectively, to
protect arrays. These layers may be removed together with the
adjacent substrate during removal of the glass after the bonding
process.
[0132] Hereinafter, a second embodiment of the present invention
will be described.
[0133] FIG. 9 is a cross-sectional view illustrating a pad, a pad
neighboring portion and an active region of an organic light
emitting display according to a second embodiment of the present
invention.
[0134] In comparison with the first embodiment, the organic light
emitting display according to the second embodiment is
characterized in that the pad electrode further includes a second
interlayer insulating film 234 between the transparent electrode
pattern 233a and the common transparent electrode pattern 235a
overlapping the transparent electrode pattern 233a.
[0135] In this case, in comparison with the pad electrode
neighboring portion, the pad electrode further includes the metal
pattern 231a, the second interlayer insulating film 232, the
transparent electrode pattern 233a and the common transparent
electrode pattern 235a. The total thickness of these layers in the
pad electrode corresponds to a third distance "d" and thus is
higher than the pad electrode neighboring portion. Accordingly, as
compared to the first embodiment, the second embodiment exhibits
superior contact properties between the touch pad electrode 2351a
of the conductive ball 455 and the dummy electrode 1400 after
bonding.
[0136] Also, the first interlayer insulating film 232 is omitted in
the active region and a step of the uppermost surface of the active
region can thus be decreased. In this case, when the protective
layer 160 covering the organic light emitting array 150 contacts
the dummy pad electrode 1400 through the sealant 450 including the
adhesive layer 400 and the conductive balls 455, the touch pad
electrode 2351a having a higher step can easily contact the sealant
455, as compared to other regions and thus exhibits improved
contact properties.
[0137] Regardless of whether the first interlayer insulating film
232 is removed from the active region, the touch pad electrode
neighboring portion has a lower step than the touch pad electrode
and thus exhibits improved contact properties.
[0138] When the first interlayer insulating film 232 is removed
from the active region, the first metal bridge 231 provided with
the thin film transistor array 140 directly contacts the first
transparent channel electrode of the transparent electrode layer
233. In this case, in order to prevent short-circuit between the
first metal bridge 231 and the first transparent channel electrode,
the first interlayer insulating film 232 may be provided on the
first metal bridge 231 excluding a contact site between first
transparent channel electrodes disposed at both sides of the first
metal bridge 231.
[0139] Hereinafter, a modified embodiment of the second embodiment
and a detailed description thereof will be described.
[0140] FIG. 10 is a plan view illustrating a region "A" of FIG. 2
according to a modified embodiment of the second embodiment. FIGS.
11A and 11B are an enlarged plan view and a cross-sectional view
illustrating a region "B" of FIG. 10, respectively.
[0141] The modified embodiment of the second embodiment according
to the present disclosure illustrates a configuration in which the
first interlayer insulating film 232 is omitted in the neighboring
portion of the touch pad portion 2350. That is, the first
interlayer insulating film 232 is formed in the active region and
the touch pad portion 2350.
[0142] Specifically, referring to FIG. 11A which is an enlarged
view of a region "B" of FIG. 10, the metal bridge 231 of the active
region is shown. Also as shown in FIG. 11B, first transparent
channel electrodes 2331 are spaced from one another in an island
form. A second transparent channel electrode connection portion
2332c between first transparent channel electrodes 2331 is disposed
in a vertical direction. A second transparent channel electrode
2332 has a diamond shape integrated therewith.
[0143] Here, the first transparent channel electrode 2331, the
second transparent channel electrode 2332 and the second
transparent channel electrode connection portion 2332c are formed
by patterning the transparent electrode layer disposed in the same
layer. The first transparent channel electrode 2331 is connected to
the metal bridge 231 through a contact hole 232a interposed between
the first interlayer insulating film 232 and the metal bridge
231.
[0144] Also, the second interlayer insulating film 234 that covers
the first transparent channel electrode 2331, the second
transparent channel electrode connection portion 2332c and the
second transparent channel electrode 2332 is formed. A common
transparent electrode 2335 having a width larger than the first
transparent channel electrode 2331 and the second transparent
channel electrode 2332 and the second transparent channel electrode
connection portion 2332c integrated with each other is formed on
the second interlayer insulating film 234.
[0145] Here, the common transparent electrode 2335 is not connected
to the pad electrode and is provided as a floating state which
functions to shield effects of driving of the organic light
emitting array disposed thereunder, when the touch electrode array
and the organic light emitting array are joined to each other using
an adhesive layer 400. If desired, the common transparent electrode
2335 may be omitted.
[0146] As shown in FIG. 10, reference numeral "231b" represents a
routing line formed together with the metal bridge 231 and is a
line to transfer a signal between the first transparent channel
electrode 2331 and the touch pad electrode 2351b of each line.
Reference numeral "231c" also represents a line formed in the same
layer as the metal bridge 231 and the second substrate (removed
after bonding), the second transparent channel electrode 2332 of
each row and the touch pad electrode (2351b, provided in a touch
pad portion formed at one side of the substrate, based on FIG.
2).
[0147] FIG. 12 is a plan view illustrating a region "A" according
to the second embodiment of the present invention. FIGS. 13A and
13B are an enlarged plan view and a cross-sectional view of a
region "C" of FIG. 12, respectively.
[0148] As shown in FIGS. 12 to 13B, according to the second
embodiment of the present invention, the first interlayer
insulating film 232 is removed from the active region, excluding a
region where the second transparent channel electrode connection
portion 2332c overlaps the metal bridge 231. In this case, the
contact hole is not provided in the first interlayer insulating
film 232 and directly contacts the first transparent channel
electrode 2331 at both sides of the metal bridge 231.
[0149] Also, the first interlayer insulating film 2232 is
selectively formed only in regions where the touch pad portion 2350
overlaps the metal bridge 231.
[0150] Accordingly, as shown in FIG. 13B, due to selective omission
of the first interlayer insulating film 2332, the top of the first
transparent channel electrode 2331 (the top of the second
transparent channel electrode 2332 has a lower step) has a lower
step than the central region of the metal bridge 231.
[0151] Also, the first interlayer insulating film 2232 is omitted
from the active region and the step of the outermost surface of the
active region can thus be lowered. In this case, when a protective
layer 160 covering the organic light emitting array 150 contacts
the dummy pad electrode 1400 through the sealant 450 including the
adhesive layer 400 and the conductive ball 455, the touch pad
electrode 2351c in the touch pad portion 2350 having a relatively
high step contacts the conductive ball 455 of the sealant and
contact properties can thus be improved.
[0152] Hereinafter, with reference to FIGS. 2, 3, 8, 10, 11A and
11B, a method for fabricating the organic light emitting display of
the present disclosure will be described.
[0153] First, an amorphous semiconductor layer 110, a first etching
stopper film 120 and a first buffer layer 130 are formed on a first
substrate 100, a thin film transistor array 140 including a thin
film transistor in each of pixels defined as a matrix form, an
organic light emitting array 150 including an organic light
emitting diode connected to the thin film transistor of each pixel,
and a protective layer 160 formed on the first buffer layer 130
such that it covers the thin film transistor array 140 and the
organic light emitting array 150 are formed in the active region of
the first buffer layer 130. A dummy pad portion including a
plurality of dummy pads 1400 spaced from one another is formed in a
part of the dead region of the first buffer layer 130.
[0154] Subsequently, a nitride film 205, a second etching stopper
film 210 and a second buffer layer 220 are formed on a second
substrate 300, the touch electrode array 230 is formed in the
active region of the second buffer layer 220, and a touch pad
portion 2350 including a plurality of touch pad electrodes (2351b
or 2351c) spaced from one another are formed in a region
corresponding to the dummy pad portion. In this process, the
configuration is designed such that the distance between the
outermost surface of the touch pad portion 2350 and the outermost
surface of the dummy pad portion is smaller than that of the
neighboring portion.
[0155] Subsequently, a sealant 450 including conductive balls 455
is applied to the touch pad portion 2350 or dummy pad portion and
an adhesive layer 400 is applied to the touch electrode array 230
or the protective layer 160 and a joining process is performed.
During the joining process, the distance between the outmost
surface of the touch pad portion 2350 and the dummy pad portion of
the pad electrode portion is smaller than that of the neighboring
portion, making connection between upper and lower pad portions
through conductive balls sufficient.
[0156] In this case, after joining, the conductive balls may be
pressed to a predetermined thickness between the touch pad portion
and the dummy pad portion.
[0157] Also, after the joining process, the dead region of the
touch pad portion neighboring portion may be spaced from the
sealant by a predetermined distance.
[0158] Also, after the joining process, the method may further
include removing the first substrate 100 and the second substrate
300 and adhering a film substrate 1000 via a film adhesion layer
1100 to the exposed surface of the first etching stopper film
120.
[0159] Here, the first substrate 100 and the second substrate 300
may be removed by etching or laser-irradiating the first substrate
100 and the second substrate 300.
[0160] Hereinafter, Tables 1 to 4 show pressing levels of
conductive balls of the configurations of FIGS. 7, 8 and 9 and a
modified embodiment of the second embodiment, a configuration shown
in FIGS. 10 to 11B.
[0161] Total numbers of conductive balls (AuB) used for structures
of respective embodiments are different. A share of a pressing
level with respect to a total number of conductive balls for
respective embodiments is important. As shown in FIGS. 3 to 5,
contact properties are improved depending on pressing level. That
is, when a thickness, to which conductive balls are pressed,
increases, contact properties are improved.
[0162] In the following test, the diameter of the conductive balls
is about 50 .mu.m.
TABLE-US-00001 TABLE 1 Total AuB pressing The number of number of
Conditions range (um) AuB (EA) Share (%) AuB (EA) Structure of 10
or less 887 70 1263 FIG. 7 10 to 15 128 10 16 to 20 204 16 20 or
more 44 3
[0163] As can be seen from Table 1 above, in the configuration
shown in FIG. 7, a diameter range of conductive balls having the
highest share of 70% among conductive balls is 10 .mu.m or
less.
TABLE-US-00002 TABLE 2 Total AuB pressing The number of number of
Conditions range (um) AuB (EA) Share (%) AuB (EA) First 10 or less
188 31 609 embodiment 10 to 15 131 22 16 to 20 207 34 20 or more 83
14
[0164] As compared to the structure of FIG. 7 shown in Table 1
above, the first embodiment shown in FIG. 8 has a decreased share
at 10 .mu.m or less of 31%, and increased pressing levels at 10 to
15 .mu.m, 16 to 20 .mu.m, and 20 .mu.m or more. This means
considerable improvement in pressing properties in all cases. Here,
a share at 10 .mu.m or less of 31% is caused by difference in
diameter between the conductive balls. When taking into
consideration the fact that a plurality conductive balls correspond
to each pad electrode, contact defects can be prevented and contact
resistance can be improved.
TABLE-US-00003 TABLE 3 Total AuB pressing The number of number of
Conditions range (um) AuB (EA) Share (%) AuB (EA) Second 10 or less
98 25 397 embodiment 10 to 15 25 6 16 to 20 89 22 20 or more 185
47
[0165] As can be seen from FIG. 9, the second embodiment exhibits
better pressing properties than the first embodiment. A pressing
range having the highest share is 0 .mu.m or more and has a share
of about 47%. Also, a pressing level of 10 .mu.m or less is 25% or
less, the conductive balls of the second embodiment exhibit better
contact properties than those of the afore-mentioned first
embodiment.
TABLE-US-00004 TABLE 4 Total AuB pressing The number of number of
Conditions range (um) AuB (EA) Share (%) AuB (EA) Modified 10 or
less 248 26 956 embodiment of 10 to 15 202 21 second 16 to 20 334
35 embodiment 20 or more 172 18
[0166] As shown in Table 4, the modified embodiment of the second
embodiment exhibits a pressing level of 10 .mu.m or less of 26% or
less which is similar to the second embodiment and conductive balls
of the modified embodiment exhibit better than those of the first
embodiment.
[0167] That is, as can be seen from these tests, according to the
embodiments of the present invention, when the touch pad electrode
has a higher step or the active region and the neighboring portion
of touch pad electrode has a lower step, a pressing level of
conductive balls increases, contact properties between upper and
lower pad portions are improved and contact resistance is
reduced.
[0168] This structure in which the touch pad electrode has a higher
step than the neighboring portion improves contact properties and
thus in-cell performance.
[0169] The organic light emitting display of the present disclosure
and the method for manufacturing the same have the following
advantages.
[0170] First, by changing a vertical configuration of the touch pad
portion or the neighboring portion in an in-cell structure having a
touch electrode array inside a cover glass, a distance between the
touch pad portion and the thin film transistor array pad portion is
decreased, as compared to a distance between other region and the
thin film transistor array pad portion, and conductive balls thus
contact upper and lower pad portions within a sufficiently
decreased distance although there is a difference in diameter
between conductive balls.
[0171] Second, a vertical distance between the touch pad portion
and the thin film transistor array pad portion is decreased and
compression properties of conductive balls during the bonding
process can thus be improved. Accordingly, contact resistance is
reduced and an in-cell structure with excellent touch sensitivity
can thus be realized.
[0172] Third, since the touch pad portion is provided on an inner
surface of the cover glass, the touch pad portion is connected to
the thin film transistor pad portion through conductive balls. All
of the touch electrode array, the thin film transistor array, and
the organic light emitting array can transfer signals through one
chip included in the thin film transistor pad portion. One chip is
connected to one flexible printed board, thus simplifying a pad
portion and circuit configurations of the organic light emitting
display. As a result, slimness and cost reduction can be
realized.
[0173] Fourth, the organic light emitting display according to the
present disclosure has an in-cell structure in which the touch
electrode array is directly formed on an inner surface of the cover
glass, thus requiring no additional process for attaching a touch
screen, enabling slimness and realizing displays manufactured in a
simple process.
[0174] Fifth, a thin film transistor array and an organic light
emitting array are formed on a first glass substrate, a touch
electrode array is formed on a second glass substrate and the
organic light emitting display array is joined to the touch
electrode array such that these arrays face each other. Then, hard
glass substrates at both sides are removed, and a plastic film is
attached to one side of an exposed surface, thus resulting in
thinness and flexibility of displays. Displays can have a reduced
thickness and increased flexibility by omitting the glass substrate
having the highest thickness.
[0175] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the inventions. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
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